The EU is to call for Northern Ireland to remain wedded to customs union and single market rules after Brexit

The EU will call for Northern Ireland to stay in its customs territory and stick to single market rules after Brexit if Theresa May cannot find a way of avoiding a hard border.

The contentious fallback option will be revealed in the withdrawal agreement legal text on Wednesday morning.

Brussels wants a “common regulatory area” on the island of Ireland if the UK government as the fallback option, an official who has seen the text has told Business Insider.

The proposals come as a leaked letter by Boris Johnson admits Brexit may cause a hard Irish border.

LONDON – The European Union will propose keeping Northern Ireland within its “customs territory” and closely aligned to its single market rules after Brexit, in the text of the withdrawal agreement due to be published today.

A well placed EU source, who has seen the text, has told Business Insider that the EU will suggest a “common regulatory area” with “no internal barriers” on the island of Ireland, if the UK government is unable to produce a workable solution to avoiding a hard border between Northern Ireland and the Republic.

The highly-anticipated document translates into legal terms the agreement reached by British and EU negotiators on the first phase of Brexit negotiations in December.

The text, which is set to be up to 120 pages long, will not explicitly call for Northern Ireland to stay in the single market if the UK government fails to come up with a workable solution, the source told BI, but will lay out areas where it could stay fully aligned with single market rules in order to maintain frictionless trade.

The European Commission is set to publish the document at around 10:00 (GMT) ahead of a press conference from the EU’s chief Brexit negotiator, Michel Barnier.

Prime Minister Theresa May has repeatedly insisted that Britain will leave both the customs union and single market as part of its imminent departure from the EU.

However, British MPs, EU officials and the Irish government have warned the prime minister that this will make physical infrastructure on the border between Northern Ireland and the Republic inevitable.

The legal text published today will suggest keeping Northern Ireland under the EU’s customs code and closely wedded to single market rules after Brexit if May is unable to come up with a way of avoiding a hard border.

It will make clear that this course of action is the default option – or the “backstop” as its known in Brussels – and other solutions to avoiding a hard border remain available, such as a comprehensive UK-EU free trade agreement.

This proposal will meet strong opposition from the Democratic Unionist Party of Northern Ireland, which currently props up May’s Conservative government.

The EU’s “backstop” would effectively move the border to the Irish sea but the Arlene Foster-led party opposes any Brexit deal based on Northern Ireland remaining wedded to the EU and moving away from the rest of the UK.

The DUP very nearly scuppered the December agreement over concerns about regulatory alignment between Northern Ireland and the Republic.

It will also irk pro-Brexit members of May’s Cabinet, like Boris Johnson and Liam Fox, who want to see the whole of Britain diverge from EU rules and regulations after Brexit.

Johnson privately told May that preventing a hard border should not be the main aim of the UK government.

The foreign secretary appeared to row back on the UK government’s previous commitment to maintaining “frictionless” trade between Northern Ireland and the Republic in an interview with BBC Radio 4 on Tuesday morning, saying that only “excessive” checks can be avoided.

“We think we can have very efficient facilitation systems to make sure there’s no need for a hard border and excessive checks on the frontier between Northern Ireland and the Republic,” the foreign secretary said.